The common theme of the Program Project continues to be the transplantation and regeneration of mammalian skeletal muscle. The overall aim of the Program Project focuses on the resolution of the basic biological mechanisms associated with the degeneration and regeneration of skeletal muscle following free whole muscle grafting, the plasticity of muscle grafts to change in activity, and the resolution of clinical problems associated with the treatment of facial palsy by the transplantation of skeletal muscles. This overall aim is addressed by the aims of the three basic science projects and the one clinical project - the International Skeletal Muscle Transplant Registry. The overall objectives of the thee basic science projects are: Bruce Carlson's Project #1 to identify the reintegrative mechanisms in free grafts, specifically the mechanisms of revascularization, the site where myogenic cells arise, the neural influences on regenerating muscle, and the myotoxic effects of local anesthetics; John Faulkner's Project #2 (funded by HL34164) to determine the mechanisms responsible for the functional deficits in free and vascularized muscle grafts, specifically the impaired function of regenerated vascular beds, the blood flow by radioactive microspheres, the maximum force generation, and the mechanism of contraction-induced injury; and Timothy White's Project #3 to determine the impact of physical activity on the structure and function of skeletal muscle grafts, specifically the effects of treadmill running, the ablation of synergistic muscles, and hindlimb suspension on myosin isoforms and fiber hypertrophy. The objectives of Charles Sing's Project #4 on the International Registry are: to develop the communications algorithm for international contacts via TELENET/BITNET satellite services, to complete records on 150 patients with facial grafts, to install the MTR computer programs in Dr. Harii's Clinic in Tokyo, and to publish papers describing the International Registry and the first lll patients registered.